Healthcare facilities require preparation and administration of very large numbers of parenteral solutions for patients. Such solutions are administered for both nutritional and therapeutic purposes, and thus efficient liquid-handling systems are required for cost-effective preparation of such solutions, and their administration to patients.
To this end, positive displacement fluid pumping devices have been developed for both preparation and administration of parenteral solutions. Such devices permit precise control during pumping of solutions, thus facilitating solution administration and preparation.
U.S. Pat. Nos. 4,639,245, to Pastrone et al., 4,818,186, to Pastrone et al., and 4,842,584, to Pastrone, all of which are hereby incorporated by reference, disclose a positive displacement fluid infusion pumping device and components thereof, which have met with widespread acceptance by the healthcare industry. This pumping system includes a combination of a pump driver and an associated removable and disposable pump cassette. The pump cassette includes a self-contained positive displacement pump device, which is operated by a reciprocable pump plunger or piston of the associated pump driver. The pump driver includes selectively operable valve actuators, which cooperate with valve mechanisms provided in the pump cassette for accurate and highly automated administration and infusion of parenteral solutions.
Commonly-assigned U.S. patent application Ser. No. 07/444,459, filed Dec. 1, 1989, now U.S. Pat. No. 5,062,774 issue Nov. 5, 1991, discloses a solution pumping system generally of the above type, including a disposable pump cassette, and an associated pump driver. The system of this application is particularly configured for automatic compounding and preparation of parenteral solutions, for subsequent infusion to a patient. This application is hereby incorporated by reference.
Solution pumping systems of the above type employ pre-assembled, disposable pump cassettes. Typically, such pump cassettes include a cassette body having juxtaposed front and rear body members, between which is positioned a membrane-like elastomeric diaphragm. The diaphragm cooperates with the front body member to provide valve mechanisms at various inlets and outlets defined by the front body member, with openings in the rear body member exposing the diaphragm for operation of the valve mechanisms by valve actuators of the associated pump driver.
Additionally, the front body member of the cassette defines a pump chamber, which, together with the internal diaphragm, provides the self-contained positive displacement pump of the cassette. The rear body member defines an opening through which a reciprocable pump piston of the associated driver is movable for operating the cassette, whereby liquid can be pumped through the cassette.
As will be appreciated, use of the above-described pumping system for preparation of parenteral solutions, or for infusion of such solutions, mandates that the system perform reliably and with a high degree of accuracy. Accordingly, such systems are ordinarily constructed to exhibit a high degree of structural integrity, with the pump cassette of such system typically constructed in a manner to all but eliminate the possibility of liquid leakage. Nevertheless, normal manufacturing variances may result in a cassette lacking the desired sealing integrity. Additionally, use of the cassette in association with the pump driver of the system may result in wear and impairment of its sealing.
Because leakage, even of a minor nature, in the pump cassette could inadvertently result in improper solution preparation, the present method contemplates a method of operating the pumping system for periodically testing the sealing integrity of the pump cassette.